Power enhancement techniques for high power satellites

ABSTRACT

A satellite is formed with a signal translation and amplification system which includes at least one communication path. Each communication path includes a plurality of radiation-cooled TWTs powered by a single EPC. Also included in the communication path is a high efficiency radiation panel capable of transmitting heat generated by said TWTs and EPC into space; as well as a radiating collector which is directly applied to each TWT, and is capable of transmitting heat generated by said TWT into space.

This is a continuation of U.S. patent application Ser. No. 08/259,987,filed on Jun. 15, 1994, now U.S. Pat. No. 5,649,310.

FIELD OF THE INVENTION

This invention relates generally to high power satellites, and inparticular, to a unique combination of high power amplifiers and heatdissipation techniques that are utilized by an earth orbiting satellite.This permits a significant increase in output power for a givensatellite size thus reducing satellite launch mass and, therefore, cost.

BACKGROUND OF THE INVENTION

A major benefit which results from providing stronger signals fromsatellite transmissions to earth based receivers is that smaller, lessexpensive, and simpler earth based satellite receive antennas ("dishes")can be employed. The use of smaller satellite dishes makes the use ofsatellite transmission more competitive with terrestrial transmissionmodes such as fiber, cable, etc., which will likely result in greateracceptance of satellite communications in general.

One technique for providing stronger satellite signals involvesincreasing the signal strength of the traveling wave tube (hereinafterreferred to as "TWT") applied to each channel, or an increase in thenumber of TWTs of similar strength being applied to each channel, in aneffort to produce a stronger signal being transmitted over each channelby the satellite. An increase in the signal strength being produced byeach TWT typically requires a careful consideration of the coolingconfiguration, since a substantial portion of the energy associated withthe production of the signal within each TWT is converted into heatenergy which must be removed.

In recent decades, design considerations for satellites, and moreparticularly communication satellites, have included providingsatellites with more power for each channel, and more channeltransmission capabilities for each satellite. These considerations havefrequently been balanced against other considerations which include theweight of the satellite. The greater the weight of the satellite(greater satellite operational lifetimes typically require satelliteswith a greater mass) generally the greater is the cost of the launchvehicle required for the satellite.

One component which is frequently used in communication satellites isthe TWT which functions as the power amplifier. A traveling wave tubeamplifier (hereinafter referred to as "TWTA") generally consists of aTWT plus its high voltage power supply (or electronic power conditioner,"EPC"). One design limitation of the TWT is that it generates aconsiderable amount of heat. Most high power communication satellitespresently use conduction-cooled TWTs. The use of conduction cooled TWTsnecessitates the use of heat spreaders and heat pipes to distribute theheat produced by the TWT, and large specialized radiating surfaces totransfer this waste heat into space. The thermal requirements, as wellas the associated satellite weight and size limitations for launch on agiven vehicle, further limit the number of high power TWTs which can becarried on a satellite of a given size.

Some TWTs are known to utilize one EPC for each pair of TWTs, thiscombination not only reduces overall power and amplifier weight but mayprovide other unrelated performance benefits. However, heat dissipationassociated with TWTs remains a major limitation on the number of TWTswhich each satellite is capable of carrying. This is generally truebecause the total heat dissipation capacity of a satellite is generallyproportional to the size of the satellite.

A method to increase the heat dissipation capacity of a satellite is toemploy TWTs which radiate a portion of the waste heat directly to space.Early radiation-cooled TWT configurations were not efficient, and thenumber of operating TWTs that a given satellite could accommodate waslimited to some small number, such as five.

From the above, it can be envisioned that a TWT configuration whichprovides more efficient cooling, less weight, and higher powergeneration per transponder than prior art systems would be highlydesirable. The present invention combines several techniques in a novelmanner to provide a high power and energy efficient satellite basedtransmitter system. As a result, the output power of such a satellite isincreased considerably without a proportional increase in size.

SUMMARY OF THE INVENTION

The present invention relates to power enhancement of a communicationssatellite through thermal design and thermal interfaces. There are anumber of improvements which contribute, and may be applied separately,to provide for a more energy efficient satellite configuration. A firstimprovement of the present invention is the application of directradiating elements to each TWT, which permits a higher quantity of heatenergy to be removed from the TWTs than by use of the conduction-cooledTWT; and thereby permits the TWTs to produce a higher power signalwithout overheating. This technique increases the overall transmittingpower capabilities of the satellite. The operation of the radiationcooled configuration is superior to (and provides a higher power output)than two conduction cooled TWTs coupled to a single EPC for a given sizesatellite.

A second improvement of the present invention is the use of an efficientradiator panel encasing a network of heat pipes. This becomes moresignificant in the configuration where two TWTs are applied to each EPCunit, since the amount of heat generated by the paired TWT units is highcompared to the single TWT per EPC configuration, and requires a moreeffective cooling ability for the amplifiers.

A third improvement is the configuration of the traveling wave tubeamplifiers such that two radiation cooled TWTs are powered by a singleEPC. This configuration provides higher transmitter power; a reducedoverall mass of the satellite; and the ability to combine the poweroutputs of the two TWTs without an on board phase adjustment which mayprovide an improved conversion efficiency. The output of the two TWTsmay be combined into a single high power output signal. Alternately, theoutput of each of the two TWTs may be a distinct signal.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a schematic illustration of one embodiment of a signalprocessing portion of the present invention;

FIG. 2 illustrates a partial cross sectional view of one embodiment of acombined TWT, radiation panel with embedded heat pipes, and collectorradiator, of a satellite 10 in accordance with the present invention,wherein the satellite is shown orbiting the earth (e1).

FIG. 3A illustrates one embodiment of a traveling wave tube amplifier ofthe prior art;

FIG. 3B illustrates an alternate embodiment of a TWTA of the prior art;

FIG. 3C illustrates a third embodiment of a TWTA of the prior art;

FIG. 3D illustrates a fourth embodiment of a TWTA of the prior art;

FIG. 3E illustrates a first embodiment of a TWTA of the presentinvention;

FIG. 3F illustrates a second embodiment of a TWTA of the presentinvention;

FIG. 4 illustrates an exploded cross sectional view of one of the heatpipes of FIG. 2;

FIG. 5 illustrates a partially broken away view of a segment of one ofthe radiation panels, with some of the heat pipes exposed;

FIG. 6 illustrates a top view of one embodiment of a full radiationpanel;

FIG. 7a illustrates radiative cooling element for a TWT, in which theradiative cooling element is formed with radiative fins;

FIG. 7b illustrates a radiative cooling element for a TWT, in which theradiative cooling element is formed with a radiative dome structure;

FIG. 7c illustrates a radiative cooling element for a TWT, in which theradiative cooling element is formed with a radiative cone structure;

FIG. 7d illustrates a radiative cooling element for a plurality of TWTs,in which the radiative cooling element is formed in two segments, eachsegment containing a plurality of radiative fins; and

FIG. 8 illustrates a headered heat pipe configuration.

Identically labeled elements appearing in different ones of the figuresrefer to the same elements but may not be referenced in the descriptionfor all figures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

In this present disclosure the term "satellite" is intended to coverstandard satellites, spacecraft, etc., and is considered as any devicewhich is capable of traveling in space. The specific values described inthe power and cooling descriptions of the present disclosure areintended to be illustrative in nature, and not limiting in scope.Elements which perform similar functions in different embodiments may beprovided with identical reference characters.

The present invention combines aspects of several technologies toprovide an enhanced signal power output per satellite while alsoproviding adequate cooling. The combination includes the utilization oftwo TWTs per an electric power conditioner (designated as "EPC" in FIG.1); the use of radiative cooling for the TWTs; and an efficientradiating panel utilizing a series of heat pipes. These technologies mayappear at times to be distinct, but they are actually quiteinterrelated.

Satellite Electrical System

Reference is now made to FIG. 1. A satellite 10 comprises a signaltranslation and amplification system 11. The signal translation andamplification system 11 includes a receiver portion 12, a signalamplification portion 13, and a transmitting portion 15.

The receiver portion includes a receiving antenna 17, a feed element 16,a band pass filter (designated as "F" in FIG. 1) 18, at least one R typeswitch 20a, 20b (R type switches are switches which are inserted inwaveguides); a plurality of receivers 21a, 21b, 21c, 21d; at least one Ttype switch 22a, 22b; an input multiplexer 24; and an input switch ring26.

The receiving antenna 17 is a commercially available antenna which isused for satellite reception of an input signal 1. The band pass filter18 blocks out the effect of the signal generated by the transmittingportion 15 which is many times stronger than any signal which is likelyto be received from any source external to the satellite. Since one ofthe primary functions of the satellite is to respond to externalsignals, the function of the band pass filter 18 becomes even moresignificant. As can be appreciated, the signal translation andamplification system 11 acts as a repeater which is carried by thesatellite 10, to receive an input signal 1, to amplify the input signal1, and to retransmit the amplified signal.

The elements described in this and the next paragraph control whichoutput group 30a, 30b, etc. of the signal 1 processing portion 13 aspecific signal will be transmitted through. The R type switches 20a,20b control which of the receivers 21a, 21b, 21c, 21d is activated, andthereby which of the receivers is connected to the receive antenna 17and the serially connected band pass filter 18. As a matter ofillustration, the R type switch 20a can selectively apply a receivedsignal to either of the upper receivers 21a, 21b. This selection istypically made depending upon which of the receivers 21a, 21b isfunctioning properly. The functioning of the receivers 21a, 21b can bemonitored from the ground, since if a receiver is not functioningproperly, there will be no output over the corresponding channel fromthe satellite. The position of the R type switch 20a is controlled fromthe ground, thereby controlling which receiver 21a, 21b is coupled tothe input signal 1 from antenna 17. If it is determined that neither ofthe upper receivers 21a, 21b is functioning properly, while both of thelower receivers 21c, 21d are functioning properly, then the R typeswitch 20a will divert its incoming signal to the lower R type switch20b to apply the signal to one of the lower receivers 21c, 21d. Theother lower receiver 21c, 21d will be connected to the antenna 17 viathe lower R type switch 20b. This configuration enables the applicationof a filtered signal from the receiving antenna 17 to any receiver, 21a,21b, 21c, 21d. The frequency of the received signal establishes whichoutput group 30a, 30b, 30c, 30d processes a specific received signal.

The plurality of receivers 21a, 21b, 21c, 21d are connected to the inputmultiplexers 24 by a plurality of T type switches 22. The receivers 21a,21b, 21c, 21d function to receive, amplify, and down-convert thereceived signal to a desired frequency. The T type switches 22a, 22b,function similarly, but in a reverse sense, to the R type switches 20a,20b described above to select any two of the four receivers 21a, 21b,21c, 21d for connection to the input multiplexers 24.

The input multiplexer 24 acts in a manner known in the art to controlwhich one of a plurality (e.g., six) of communication paths 40a, 40b ofthe signal processing portion 13 the signal may be applied to withineach output group (only communication paths 40a and 40b of output group1 are illustrated for the purposes of display clarity). The inputswitching ring 26 operates to select, by example, four specificcommunications paths from six available communication paths (onlycommunication paths 40a, and 40b, are illustrated) within. For example,if one (or more) of the selected communications paths becomesnon-functional, the switching ring 26 is re-configured by ground commandto select one of the unused (redundant) communications paths. In FIG. 1,the letter "T" associated with the switching ring 26 represents afunction of the switching ring 26 to transmit signals received from theinput multiplexer 24 to the selected communication paths. The inputmultiplexer 24 and the switching rings 26 are both commerciallyavailable, and will not be further detailed herein.

The signal amplification portion 13 of FIG. 1 comprises a plurality ofoutput groups designated as, by example and for the purposes ofillustration, "output group 1 30a, output group 2 30b, output group 330c, and output group 4 30d, respectively". Output group 1 30a andoutput group 2 30b may be disposed on, by example, a first radiationpanel (Panel I), and output group 3 30c and output group 4 30c may bedisposed on, by example, a second radiation panel (Panel II). Eachoutput group comprises a plurality of communication paths 40a, 40b (twocommunication paths are illustrated in the output group 30a of FIG. 1,but there are 6 communication paths in each output group.) Four of theoutput groups are active (selected) at any given time, and the remainingtwo are redundant. Each communication path includes a channel amplifier45 and a TWTA 48. The channel amplifier 45 serves as a preamplifier forthe signal to be applied to the TWTA 48.

Each TWTA 48 of FIG. 1 comprises an input hybrid 53, an output hybrid(designated as "HYB" in FIG. 1) 55, and two TWTs 50a, 50b which arepowered by one EPC 52. This TWTA configuration provides for improvedpower conversion efficiency as well as reduced mass. The use of a commonEPC 52 also provides the ability to combine the RF output power of thetwo TWTs 50a, 50b without requiring on-board phase adjustment.

Each TWT is configured to contain a collector radiator 70 (see FIG. 2)which is positioned to be exposed external to the satellite 10, and assuch provides a primary path for heat rejection. The collector radiator70 has a plurality of radiating fins 70'. It is envisioned that each ofthe two TWTs in each of the communication paths could be applied toamplify signals of distinct channels, and thus act separately.Alternately, the two TWTs 50a, 50b could both be applied to the samechannel, as shown in FIG. 1. When the TWTs are combined, the signalstrength of the TWTs is nearly doubled (it is not actually doubled dueto combining losses.) However, the total number of available satellitetransmitter channels is also halved. The input hybrid 53 divides thesignal strength applied to each TWTA 48 into two substantially evenamounts, which are applied to each TWT 50a, 50b.

The transmitter portion 15 includes an output switching ring 62, anoutput multiplexer 64, a feed element 67 and a transmitting antenna 68.The output ring 62 acts in a known manner, in combination with the inputring 26, to provide the suitable number of properly functioningcommunication paths from each output group 30a, 30b, 30c, 30d at anygiven time; and to eliminate non-functional communication paths. Theoutput multiplexer 64 combines the transmissions of all of the signalsapplied from all of the communication paths within each output group30a, 30b, etc., such that the signals will be transmitted over a singleelectrical conduit 66 to the antenna feed 67. In FIG. 1, the letter "R"associated with the output switching ring 62 represents a function ofthe output switching ring 62 to receive signals from the selectedcommunication paths, whereafter the signals are supplied to the outputmultiplexer 64.

Whatever signal is transmitted from the output-multiplexer 64 will betransmitted by a respective antenna (each antenna is denoted as "68" inFIG. 1) as an output signal (e.g., such an output signal is denoted inFIG. 1 as "output signal 1" for a first one 68 of the antennas, and as"output signal 2" for a second one 68 of the antennas). Each satellite10 may contain a plurality of the transmitting antennas, each of whichis targeted to a unique location (covering distinct land masses, orother satellites, etc.). Each transmitting antenna 68 receives outputsignals from one or more output groups 30a, 30b, etc. in the FIG. 1embodiment. The FIG. 1 embodiment is intended to be illustrative innature, and not limiting in scope.

Radiation Cooling

The radiation cooled TWTs 50a, 50b and EPCs 52 are mounted on highefficiency radiation panels 54 as illustrated in FIG. 2, in which thebulk of each radiation panel is formed from an aluminum honeycomb withoptical solar reflectors (OSR's) 71 on the radiating side. The OSRs 71permit heat energy to pass from the radiation panels 54 into space,while reflecting a high percentage of ambient radiation back into space,as is well known in the art. Each radiation panel 54 employs a pluralityof parallel embedded heat pipes 58 which are mounted substantiallyperpendicularly to a plurality of parallel embedded heat pipes 59. Thisconfiguration functions to substantially evenly dissipate heat generatedby the TWTs and EPCs throughout the radiation panels 54 and into space.A cooling fluid such as ammonia is sealed in channels 60 formed in eachembedded heat pipe 58, 59 and provides a heat sink for the heat appliedto the radiation panel 54.

It is preferable that the heat pipes 58, 59 be oriented in a crossedarrangement as illustrated. This configuration provides a very efficientheat radiator, permitting the development of a higher power, more energyefficient and lower mass satellite for a given volume than could beachieved otherwise. Heat energy passes by conduction from the TWTs 50a,50b, via the radiation panel 54, to the heat pipes 58, 59. When the heatenergy is in the heat pipes, it is distributed more evenly throughoutthe heat pipes, and through the radiation panel into space.

To accommodate components of high concentrated heat loads, heat pipesare used to spread the heat efficiently over the entire OSR 71.Referring to FIG. 4, the fixed-conductance, dual channel heat pipes 58,59 are preferably formed with axially grooved aluminum tubing withanhydrous ammonia used as the working cooling fluid. In FIG. 4, thetubing is labelled as "60a" and the axial grooves of the tubing arelabelled as "60b". Each dual channel heat pipe 58, 59 consists of thetwo independently operating channels 60. The components are arrangedsuch that failure of a single heat pipe channel in a dual channel heatpipe will not overly limit the cooling capabilities of any of the heatpipes 58, 59; and thereby not impinge upon the overall operation of thesatellite 10.

The heat pipe layout for each radiation panel 54 (there are typicallytwo radiation panels (Panel I and Panel II) per satellite) is configuredin a matrix arrangement (see FIGS. 5 and 6) with a total of 13 longerlateral heat pipes 59, and 6 header heat pipes 58 (as illustrated inFIG. 6.) As can be seen in view of FIG. 2, the lateral heat pipes 59 arebonded to an inner communication panel faceskin 100 (see FIG. 2), andcome in direct contact with as much of the TWTs 50a, 50b and the EPCs 52as is possible due to design constraints. The header heat pipes 58contact each crossing lateral heat pipe 59. Heat energy is transmittedeffectively between the header heat pipes 58 and the lateral heat pipes59. In FIG. 6, a recess 120 is formed in the radiation panel to permitan arm for connecting to the solar array (not illustrated) to extendthrough.

As can be observed from FIG. 2, heat generated by the TWTs 50a, 50b (andalso the unillustrated EPCs 52), can be transferred into space viaeither a collector radiator 70 or the radiation panel 54. The collectorradiator 70 is typically integrally formed with the radiation-cooledTWTs, and provides a passage for heat energy directly into space. Athermal shield 72 is provided to limit the heat energy which has passedfrom the TWTs 50a, 50b to the collector radiator 70 from passing back tothe TWTs. This combination promotes the passage of heat energy intospace.

While the prior art conduction-cooled TWTs utilize heat sinks as thermalspreaders to uniformly distribute the thermal energy, theradiation-cooled TWTs of the present invention utilize radiation panels,which contain heat pipes, to distribute at least a significant portionof the remaining TWT heat (the remaining heat is the total TWT heat lessthat radiated to space by the TWT radiating collector.) The radiationpanels utilize the high thermal conductivity of the heat pipes touniformly distribute the heat across the panel. Heat distribution withheat sinks and spreaders (thick panel face skins) is much heavier thanradiation panels utilizing heat pipes. The collector radiators 70combine with the radiation panels of the present invention to radiatesufficient heat energy into space so that the TWTs can produce the highenergy level associated with the powerful signals while not overheating.

Prior art satellites, limited in size, weight, and launch vehiclefairing envelopes can handle approximately 5000 watts DC, and less than2000 watts RF radiated power. The present configuration permits 10,000watts DC, or approximately 4200 watts RF radiated power. Table 1 is acomparison of the present invention and prior art TWTA performance andcooling characteristics. The prior art configurations are illustrated inFIGS. 3A to 3D, and correspond to each of the "prior art embodiments"illustrated in Table 1, as described therein. FIG. 3A illustrates anexample of a prior art embodiment referenced in Table 1 comprising oneTWT 90 and an EPC 92. FIG. 3B illustrates another exemplary prior artembodiment wherein there are two TWTs 90, each one being powered by arespective individual EPC 92. A phase shifter 91 is coupled to an inputof one of the TWTs 92. Outputs of both of the TWTs 90 are coupled to asummer 93. In FIG. 3C, another exemplary prior art embodiment referencedin Table 1 is shown wherein there is a single TWT 90 powered by a singleEPC 92. The TWT 90 is provided with heat radiation means 94. FIG. 3Dillustrates yet another prior art embodiment referenced in Table 1comprising a pair of TWTs 90 powered by a single EPC 92. Outputs of theTWTs 90 are provided to a summer 93. The present invention configurationis illustrated in FIGS. 1, 3E and 3F and corresponds to the "presentinvention embodiments" of Table 1. FIG. 3E illustrates an example of oneembodiment of the present invention referenced in Table 1 comprising twoTWTs (e.g., TWT 50a, and TWT 50b) powered by a single EPC (e.g., EPC52). Each TWT is provided with a radiator 96, which in FIG. 3Ecompositely represents the collector radiator 70 and the radiation panelheat pipes 58 and 59 shown in FIG. 2. Outputs of the TWTs 50a, 50b, arecombined by, for example, a hybrid 55. FIG. 3F illustrates anotherexemplary embodiment of the present invention that is referenced inTable 1 comprising two TWTs (e.g., TWT 50a and TWT 50b) powered by asingle EPC 52. Each TWT 50a, 50b is provided with an associated radiator96 similar to that in FIG. 3E. Outputs of the TWTs 50a, 50b are notcombined.

                                      TABLE 1    __________________________________________________________________________    PRIOR ART EMBODIMENTS    Satellite body                2.7 × 2.4 × 2.7                       2.7 × 3.4 × 3.2                              2.7 × 3.4 × 3.2                                     2.8 × 3.4 × 3.8    Dimensions (meters)    Fig. where illustrated                3A     3B     3C     3D    Number of Transponders                36     36     4      16/8    Transmitter Power per                55 W   75/150 W                              230 w  120/240 W    Transponder    Total RF Transmitter Power                929 W  1,400 W                              920 W  1,920 W    Satellite DC Power                3,500 W                       5,000 W                              3,300 W                                     5,000 W    Transmitter Configuration                1 EPC  2 EPC  1 EPC  1 EPC                1 TWT  2 TWT plus                              1 TWT  2 TWT                       phase shift    TWT Cooling Conduction                       Conduction                              Radiation                                     Conduction    Combinable TWT for                no     yes    no     yes    Power Increase    Heat Pipes  yes    yes    yes    yes    PRESENT INVENTION EMBODIMENTS    Satellite Body   2.7 × 3.4 × 2.7                                2.7 × 3.4 × 3.2    Dimensions (meters)    Figure where illustrated                     1 and 3E or 3F                                1 & 3E or 3F    Number of Transponders                     32/16      32/16    Transmitter Power per                     107/208 W  137/263 W    Transponder    Total RF Transmitter Power                     3,424 W    4,384 W    Satellite DC Power                     8,000 W    10,000 W    Transmitter Configuration                     1 EPC      1 EPC                     2 TWT      2 TWT    TWT Cooling      Radiation  Radiation    Combinable TWT for                     yes        yes    Power Increase    Heat Pipes       yes        yes    __________________________________________________________________________

As evident from Table 1, the present invention provides a considerableimprovement over the signal power generated compared to the prior artembodiments. The ground receivers (satellite dishes) which areconfigured to receive signals from the satellite of the presentinvention can be constructed to be smaller than the prior art satellitedishes due to the stronger signal generated by the satellites, whilestill receiving a comparable signal strength. This permits the use ofless expensive, less obtrusive satellite dishes than those required withthe present generation satellites. The use of smaller, less spaceconsuming satellite dishes further enables a greater use of satellitecommunications in general.

Alternate Present Invention Embodiments

FIGS. 1, 2, 3E, 3F, 4, 5, and 6 illustrate different aspects of oneembodiment of the present invention. It should be emphasized that thereare several modifications which can be made to the above embodimentwhile remaining within the scope of the present invention.

For example, the collector radiator of FIG. 2 has radiating fins toprovide radiative cooling from the TWTs. Alternate embodiments of TWTradiation cooling surfaces are illustrated in FIGS. 7a-7d. FIG. 7aillustrates a TWT 50a similar to the one shown in the FIG. 2, whereinthe TWT 50a has a collector radiator 70 including a plurality ofradiating fins 70'. FIG. 7b illustrates a TWT 50a having a collectorradiator 70 which includes a dome radiating cooling element 150a. FIG.7c illustrates a TWT 50a having a collector radiator 70 with a coneradiating cooling element 151. FIG. 7d illustrates a plurality of TWTs50a including a collector radiator 70. The TWTs 50a of FIG. 7d are bothcooled by a distinct radiation portion 154, including fins 155, formingthe collector radiator 70; each radiation portion has a plurality ofradiating fins which are intertwined. Any other suitable radiatingdevice which may be affixed to a TWT to radiate heat into space iswithin the scope of the present invention.

FIGS. 5 and 6 illustrate an exemplary embodiment of the inventionwherein heat pipes 58, 59 associated with radiation panel 54 arecross-hatched. The heat pipes 58, 59 have operating channels 60 (FIG.5). The benefits of cross-hatching the heat pipes has previously beendescribed. However, it is also within the scope of the present inventionto provide heat pipes 160 in a headered configuration as illustrated inFIG. 8. The headered configuration has also been found to distributeheat energy effectively across a relatively large radiation panel 161(thereby assisting in radiative cooling.) Recess 120 is also shown inFIG. 8. Any suitable heat pipe configuration which provides efficientheat distribution across a radiation panel is within the scope of thepresent invention.

While several embodiments are disclosed in this specification, thisspecification is not intended to be limiting in scope, otherconfigurations which are within the scope of the claims are intended tobe included within the scope of the present invention.

What is claimed is:
 1. An earth orbiting satellite carrying an RFtransceiver payload having a signal translation and amplificationsystem, the signal translation and amplification system comprising:atleast one RF energy communication path comprising a plurality ofradiation-cooled traveling wave tubes (TWTs) powered by a singleelectronic power conditioner (EPC), each TWT of the plurality of TWTscomprising a respective radiator component that is thermally coupled tothe corresponding TWT for providing a primary path of radiating heatinto space; and a high efficiency radiation panel that is thermallycoupled along a first major surface thereof to each of said plurality ofTWTs and to said EPC for providing a separate path of transferringthermal energy therefrom, said radiation panel comprising thermaltransfer means for transferring the thermal energy from said first majorsurface to a second, opposite major surface whereat the thermal energyis radiated into space, wherein said thermal transfer means is comprisedof a plurality of embedded heat pipes, wherein each embedded heat pipecontains a plurality of fluid-containing channels, and wherein byradiating said heat and said thermal energy into space, said radiatorcomponent and said thermal transfer means enable said RF transceiverpayload to provide increased output power relative to an RF transceiverpayload which does not include these components.
 2. A signal translationand amplification system as set forth in claim 1, wherein said pluralityof embedded heat pipes define a cross-hatched network for approximatelyuniformly distributing the thermal energy over an area of the radiationpanel, and wherein laterally disposed ones of said embedded heat pipesare affixed to an inner faceskin surface of said radiation panel.
 3. Asignal translation and amplification system as set forth in claim 1,wherein said respective radiator component includes a correspondingplurality of radiating fins.
 4. A signal translation and amplificationsystem as set forth in claim 1, wherein said respective radiatorcomponent includes a corresponding cone-shaped radiating coolingelement.
 5. A signal translation and amplification system as set forthin claim 1, wherein said respective radiator component includes acorresponding dome-shaped radiating cooling element.
 6. A signaltranslation and amplification system as set forth in claim 1, whereinsaid plurality of embedded heat pipes define a cross-hatched network forapproximately uniformly distributing the thermal energy over an area ofthe radiation panel.
 7. A signal translation and amplification system asset forth in claim 1, wherein said radiation panel is further comprisedof a solar radiation reflector that is disposed over said second majorsurface, said solar radiation reflector for reflecting solar radiationenergy impinging on said second major surface back into space.
 8. Asignal translation and amplification system as set forth in claim 1, andfurther comprising:at least one receive antenna for receiving RF energytransmissions from a terrestrial station transceiver, said at least onereceive antenna having an output thereof coupled to an input of each ofsaid plurality of TWTs; and at least one transmit antenna fortransmitting amplified RF energy transmissions from said plurality ofTWTs to a terrestrial station receiver, said at least one transmitantenna having an input thereof coupled to an output of each of saidplurality of TWTs.
 9. A signal translation and amplification system asset forth in claim 1, wherein each fluid-containing channel has arespective axially grooved channel surface.
 10. A signal translation andamplification system as set forth in claim 1, wherein said radiationpanel comprises a cellular structural material in which said pluralityof embedded heat pipes are embedded.
 11. An earth orbiting satellitecarrying an RF transceiver payload having a signal translation andamplification system, the signal translation and amplification systemcomprising:at least one RF energy communication path comprising aplurality of radiation-cooled traveling wave tubes (TWTs) powered by asingle electronic power conditioner (EPC), each TWT of the plurality ofTWTs comprising a respective radiator component that is thermallycoupled to the corresponding TWT for providing a primary path ofradiating heat into space; and a high efficiency radiation panel that isthermally coupled along a first major surface thereof to each of saidplurality of TWTs and to said EPC for providing a separate path oftransferring thermal energy therefrom, said radiation panel comprisingthermal transfer means for transferring the thermal energy from saidfirst major surface to a second, opposite major surface whereat thethermal energy is radiated into space, wherein said thermal transfermeans is comprised of a plurality of embedded heat pipes, wherein eachembedded heat pipe contains a plurality of fluid-containing channels,wherein by radiating said heat and said thermal energy into space, saidradiator component and said thermal transfer means enable said RFtransceiver payload to provide increased output power relative to an RFtransceiver payload which does not include these components, whereinsaid respective radiator component is disposed externally to an outersurface of said satellite, and wherein said signal translation andamplification system further comprises a thermal shield disposed over atleast a portion of said outer surface between said outer surface and atleast a portion of said respective radiator component, said thermalshield for preventing said heat energy from travelling back to thecorresponding TWT.